From PETER D. MOORE
Your news item on the mastodon from Ohio (New Scientist, Science, 1
June) raises a number of interesting questions, one of which is whether
we can derive a picture of the vegetation of 11 000 years ago from an analysis
of its gut contents. Your reporter suggests that the animal’s diet of water
plants rather than the expected fir and spruce twigs indicates an open,
unforested environment.
This may well be true, but is not acceptable as proof since the animal
may have been deliberately exercising a dietary preference in selecting
water plants from the available vegetation. There is, in fact, a very telling
demonstration of such selection in the modern boreal environments of Canada
by the extant megafaunal animal, the moose.
Work by Botkin and others in the Isle Royale National Park in Canada
showed that the moose spends its summer grazing upon water plants in preference
to spruce and other trees. They put this down to the fact that the aquatic
vegetation contains up to a thousand times more sodium per unit weight than
coniferous twigs and without this essential supplement to their diet the
animals would be suffering from a serious sodium deficiency.
The mastodons of late-glacial Ohio clearly had a similar dietary preference,
and their gut contents should be interpreted not as a basis for the reconstruction
of past vegetation, but as a fascinating insight into the nutrient dynamics
of an ancient ecosystem.
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Peter D. Moore King’s College London
